I know you are but what am I?
A stupid kid’s answer to a stupid kid’s insult. It’s like saying 'You’re stupid' and then giving up.
'You’re a baby!' I said, 'I know you are, but what am I?' and sat down.
He said I was a nerd. I said, 'I know you are, but what am I?' and left.
She said I was a dork. I said, 'I know you are, but what am I?' and got a snack.